On board means of transport, such as aircraft, buses, trains or ships, usually numerous apparatuses are arranged at different and often also variable positions. Some of such means of transport are, for example, equipped with passenger supply modules (often also referred to as passenger service units or personal service units (PSUs)), in order to supply passengers of the means of transport individually or display information.
The passenger cabin of a modern commercial aircraft is normally fitted with a multiplicity of PSUs which are each assigned to one passenger seat row and are arranged underneath overhead luggage compartments in a position accessible to the passengers sitting on the passenger seats. A typical PSU, as described for example in DE 10 2009 058 849 A1, comprises a loudspeaker, a display element, on which for example a fasten seat belt sign is displayed, as well as one or more reading lamp(s). Furthermore, an individually adjustable air nozzle is integrated in a conventional PSU for each passenger seat of a seat row.
In conventional cabin architectures of aircraft, the seats and accordingly also the seat rows are arranged at fixed seat positions, i.e. aircraft usually have a fixed cabin architecture. To each seat row there is usually assigned a PSU. Accordingly, above each seat row in each case at least one PSU is arranged and installed. In order to be able to carry more or fewer passengers, if required, in subregions of the aircraft cabin or the entire aircraft cabin, increasingly a more flexible cabin layout is sought. For this purpose, the seats may be displaced to increase or decrease the seat spacing in the longitudinal direction of the aircraft. Accordingly, in some cabin architectures the PSUs may be repositioned.
Several or all of the PSUs of a means of transport are normally each coupled to an interface of a so-called Decoder Encoder Unit (DEU). In conventional aircraft architectures, a DEU of type A (DEU A) forms the interface between the “Cabin Intercom and Data System” (CIDS) and the systems relevant to the passengers. A DEU A can supply a plurality of, e.g. up to three, passenger seats and is usually laid above the seats along the entire cabin. With the CIDS it is possible to check, monitor and test numerous cabin systems. For example, announcements to passengers, the internal communication of the flight crew, the illuminated warning and information signs, the general cabin lighting, the lighting of the escape routes, and entertainment systems (video, music; in relation to aircraft normally referred to as In Flight Entertainment (IFE)) are managed by the CIDS. The communication between the central computer of the CIDS (the so-called director) and the cabin systems takes place via the said DEUs.
In order to control functionalities of the PSUs, e.g. electrical functionalities such as the loudspeaker output or the output of information on the display element, usually an indirect addressing of the PSU to be controlled takes place by means of the DEU interface to which the PSU to be controlled is attached. The indirect addressing of the PSUs by means of the DEU does not allow the physical installation position, i.e. the actual position of the PSU, to be deduced. The correlation between logic address and physical position, for example the assignment of the PSU to the corresponding seat row number in the cabin, usually takes place manually by the installation personnel.
Although methods for network-wide topology recognition using network protocols such as the Link Layer Discovery Protocol (LLDP) or measurement of cable lengths/transmission times by means of the Precision Time Protocol (PTP) enable a very accurate determination of the logic sequence of apparatuses, such as PSUs, connected to the DEU, they do not allow the actual arrangement of the terminal equipment, such as its position, in the cabin of the means of transport to be deduced.